Process for integral or through coloration of marble.



' marble tojbe colorcd, In fact,people proceededto marble coloringexactly as if silksuiw'fru snar s Parana curios;

- ERNESTO LORENZO BELLONI, or MILAN, ITALY} PROCESSFOR meem on THROUGHCOLORATION OF MARBLE.

' To all whom z',t 1r'1lty concern:

Be it known-that I, ERNESTO LORENZO ,BILLONI, a subject'o'f the King ofItaly," r'esiding at Milan, Italy, have invented cep'tain new and usefulImprovements in P occss for Integral or Through Coloration of Marble, ofwhich the following'is a specification.

Mai'blecoloring, though known long ago, has never ar sen to anindustryproper, owing .to the unconquered difficulty of thorough penetration ofthecoloring matter through the mass of the marble.

{It is known that white marble-from which colored marble -is' Obtained,is an eminently crystalline material--that is, to say, its constituentparticles are not gasually'aggregated to -each other, but arrangedacco'rding'to such geometrical structureplansthat the whole of,

' its mass is permeated by the capillar tubes formed by theintercrystallinespacesl Various attempts were made to fillthesaid spaceswith coloringsubstances, "but most of them were unsuccessful, owing totheir being no clear intelligence of the behavior of the coloringsubstances as to the mass of the -were .to be dyed, and the onlypointwasjto study a color capable of being permanently fixed on itssubstratum, without ascertaining whether the character of such coloringsolution was adapted toallow of deep penetration inside the mass, orinstead of giving the solution this strength of' penetration-attemptswere-made to overcome by 'mechanical external means the resistanceopposed to penetration, such as the useofvacuum' and pressure, to obtainan integral or through coloring. .40

-Although marble seems to be a material easily impregnated by coloringsubstances, it presents very. great difficulties in coloring, owingtothe fact that thercnot being any nexus between the coloring substanceand the material of the marble the said coloring substance is liable tobe'easily'altered by atmos- I phericalagents. i v

In order to obtain an unalterable coloring of marble, the latter mustbe, as much as possible, combinedby chemical aifinity'with the coloringsubstance, whence the necessity to form thecoloring pigment within themarble,'

' so as to enable thelatter to participate of the reaction when thistakes place.

It is therefore obvious that owing to the necessity of I Specificationof Letters Patent. Application tiled July 16,1906. 'Serial N0. 326.409.

Patented Feb. 19; 1907.

using different salt solutions designed to act "the one after the otherintegral marble coloring is far from being an easy matter, as ifthefirst salt solution easilygets access through the numerousintercrystalline spaces'of the marble the subsequent ones willfindltheaccessobstructed by the residues of the first impregnation, whereby thesubsequent ini- .pregnations will always be more superficial than thepreceding ones, so that in the center} of the mass color will bewantingMThe -m'arblc,.either in the form of sawedslabs or in biglblocks;is to be considered as a porous wall where the intercrystalline poresrepresent as 'manycapillar tubes 'in which for determined physicalpowers the coloring salt solutions act. It is proved by physical lawsthat a salt solution has a greater'power of'penctrats ing through aporous wallthe more concentrated. the said solution is.

. I It will be seen that the marble when'not' yet subjected'to anycoloring treatment has i a number of pores in its interior to allow ofthe, easyaccess of the elements of any neutral salt solution; but onrepetitionpf this treatment, after one or more solutions hav ingdeposited their residues in the said pores,

the passage will become more and more narrow, opposing an increasingresistance to the further penetration of the said elements into thedepth of the marble, which resistance must beovercome by giving thesubsequent solution-a-greater power of penetration than the precedingones, which is obtained, as has been said, by a higher degree ofconcentration of the solution. This is the only means for practicallyobtaining integral or through coloringof marble.

, By way of exampge', suppose whitemarb le is to be red colored yferrocyanid' oftcopper, I then introduce th'epiece of marble into aneutral or alkaline solution of a copper salt,

of concentration of'same. Now the alkaline I ferrocyanid finds no, morethe easy access as before, as besides the'resi stanceopposed by onalresistance" pper salt depaces which and it is the assa e e solution ahigrier initial resistance of marble plus that of the first solutionwillneed a penetrating power equal to 2 in order to arrive at the same depthX,- this being a necessary condition to have all of the copper salttransformed into ferrocy anid and the coloring become uniformthroughout.

My present marble-coloring process bemg based on thc principle of thecoloring solutions used being of difierent degree of concentration; itwill be understood that the operator will be in a position to obtain anycoloring effect in the marble.

obtain a uniform rose color in the marble whenvery much dilutedsolutions are used and a red and blue 'color when so using concentratedsolution that the degree of concen- 'tration of the second solution isnot too much higher than that of the first one. Fur thermore, invertingthe use of the two solutions-that is to say, first impregnating themarble with an alkaline ferrocyanid solution and then with an ammoniacalcopper solution, provided they be of progressive concentration, I'willobtain an integralcoloring of a line rose green due to the complementarycoloring composed of the blue of the copper salt in excess, the red ofthe ferrocyanid, and

thewhite of the marble.

Of course, in order that the operator may be able to obtain differenteffects of shadowing and marbling he must know the chem ical andphysical structure of the marble to be colored, which presents in itsmass differences of structure and composition which may be takenadvantage offor easily obtaining marbling effects in coloring similar tothose observed in natural colored marbles, as nature in'its slow processof coloring has exclusively taken advantage of them to produce theinfinite variations of color found 111 natural marbles it 1s alsonecessary to be able to control at will the concentration of thesolutions. To obtain this, we are assisted by physics, by which we aretaught that the osmotic power of a salt solution is given by the sum ofthe osmotic powers which the salt elements constituting the solutionwould exercise it each of them would act in an equal quantity of liquid.Thus, for instance, while a water solution of potassic ferrocyanid cannever have a higher density "thick blocks, .a thing that appears to hav'Y Thus in theabove example by means of copper salt andalkalineferrocyanid solution 1 am able to cent. wit 'sodic ierrccy ids generallyits deitie increased atwill and the solution such penetrating power I Jobtain the eiiect air The fact 'oibeing able to give the olution at willany degreeci concentration is-also of great importance in integral marbcoloring, especially when applied to ve never been provided by any onehitherto dealing with marblecoloring, and to this due the had success incoloring big block-sci slabs ofiering a greatresistanoe to penetra tion.This penetrating power will be further increasedby the intervention ofrest b y causing it toact directly on the coloring solutions 7 andslightly heating-the marble which will then give up part of its heat tothe solution into which it will be immerged, thus raising its initialthermic degree. To this purpose I may, for instance, proceed as follows:The marble, in sawed slabs or big blocks, is first introduc ed into anair-currentdrying chamber to expel all ofits humidity from it, the saidair-current being dried by being caused to pass through a burnin-furnace, which-besides drying heats it materially, whereby a sensibleheating of the marble is produced, which when kept below 100 centigradeis unable of deteriorating its compactness and accelerates very much itsdrying. The marble when thoroughly dried. but still hot, is immergedinto suitable salt solutions, which may have the temperature of thesurrounding atmosphere or be slightly heated. By all means it will benecessary that the diflerence between the temperature of the marble andthe solution be not too great, it being no very good heat-conductor, andthat the total heat be not excessive, as in thiscase the compactness ofmarble would suffer. In general the rise of temperature of a few degreesabove .the normal one, furnished by the marble when immcrged slightlyheated into the solution, will "be quite sufiicient. When the firstimpregnation is completed, a new drying is necessary, which in this casewill be much facilitated by the intervention of heat, and this operationwill be repeated again and again until the desired color and intensityare obtained.

Having now fully described my said invention and the manner in which thesame is to be performed, what I claim, and desire to secure byLettersPatent oi the United States, is i 1. The herein-described processof coloring marble which consists in subjecting said marble successivelyto the action otsalt solutions of gradually-increased osmotic power.

2. in the process of coloring marble, the step of obtaininghighly-concentrated salt solutions which consists in first obtaining:ithe iii'sii-nzunoi'i radical, subsrantiaib; il-S desaim'zited solutionoi the zuriil radical of iiw scribed.

boss (iCSiKWi and then increasing the (legion in testimony \x'horooi' Ihave aflixed my of concentration of Hiliii solution by the insignaturein presence of two witnesses. uroiiuction of fresh qnnntitivs of theacid 3 l-llixils'ioLORENZO BBLLONL [L -i radical of the said basecinnbinmi with :1- mdiviitnvsses:

0M different from the iilSi-IIILHHLi acid roilii G. B. ZZANARDO,

said Miami being soiubie in solvents of ERNEST .i. SANTL

